Seasonal Trends in Acoustic Detection of Marine Mammals in Baffin Bay and Melville Bay, Northwest Greenland

The expansion of hydrocarbon exploration in northwest Greenland has made it increasingly important to understand the occurrence of marine mammals in the region. We describe the seasonal occurrence of marine mammals and the spatial distribution of their calls in Baffin Bay and Melville Bay. Four Autonomous Multichannel Acoustic Recorders (AMARs) were deployed during summer 2012 (late July to early October), five recorders during September 2013, and two recorders from late September 2013 to early September 2014. The call presence of several species was analyzed using automatic call detection and manual verification analysis methods. A novel approach to discern narwhal (Monodon monoceros) clicks from beluga (Delphinapterus leucas) clicks was implemented during the verification process. Narwhal calls were detected in spring and fall, showing a south-to-north migration pattern in spring and a north-to-south migration pattern in fall. Few beluga whales were detected during fall 2013 and spring 2014. Bearded seal (Erignathus barbatus) calls were detected mainly during spring (mating period). A small number of bowhead whale calls (Balaena mysticetus) were detected during fall 2013 and spring and summer 2014. For the first time at this latitude in Baffin Bay, long-finned pilot whales (Globicephala melas) and sperm whales (Physeter macrocephalus) were detected during summer and fall. Our results suggest that the presence of marine mammals in Baffin Bay and Melville Bay is governed mainly by the annual cycle of sea ice formation and decay

The beat goes on : humpback whale song seasonality in Antarctic and South African waters

Little is known of the movements and seasonal occurrence of humpback whales (Megaptera novaeangliae) of South Africa and the Antarctic, populations once brought to near extinction by historic commercial whaling. We investigated the seasonal occurrence and diel-vocalizing pattern of humpback whale songs off the west coast of South Africa (migration route and opportunistic feeding ground) and the Maud Rise, Antarctica (feeding ground), using passive acoustic monitoring data collected between early 2014 and early 2017. Data were collected using acoustic autonomous recorders deployed 200-300 m below the sea surface in waters 855, 1,118 and 4,400 m deep. Acoustic data were manually analyzed for humpback whale vocalizations. While non-song calls were never identified, humpback whale songs were detected from June through December in South African waters, with a peak in percentage of acoustic occurrence around September/October in the austral spring. In Antarctic waters, songs were detected from March through May and in July (with a peak occurrence in April) where acoustic occurrence of humpback whales was negatively correlated to distance to the sea ice extent. Humpback whales were more vocally active at night than in the day at all recording sites. Detection range modelling indicates that humpback whale vocalizations could be detected as far as 18 and 45 km from recorders in South African and Antarctic waters, respectively. This study provides a multi-year description of the offshore acoustic occurrence of humpback whales off the west coast of South Africa and Maud Rise, Antarctica, regions that should continue to be monitored to understand these recovering populations.The South African National Antarctic Programme.https://www.frontiersin.org/journals/marine-science#dm2022Mammal Research InstituteZoology and Entomolog

Seasonal Trends in Acoustic Detection of Marine Mammals in Baffin Bay and Melville Bay, Northwest Greenland + Supplementary Appendix 1 (See Article Tools)

The expansion of hydrocarbon exploration in northwest Greenland has made it increasingly important to understand the occurrence of marine mammals in the region. We describe the seasonal occurrence of marine mammals and the spatial distribution of their calls in Baffin Bay and Melville Bay. Four Autonomous Multichannel Acoustic Recorders (AMARs) were deployed during summer 2012 (late July to early October), five recorders during September 2013, and two recorders from late September 2013 to early September 2014. The call presence of several species was analyzed using automatic call detection and manual verification analysis methods. A novel approach to discern narwhal (Monodon monoceros) clicks from beluga (Delphinapterus leucas) clicks was implemented during the verification process. Narwhal calls were detected in spring and fall, showing a south-to-north migration pattern in spring and a north-to-south migration pattern in fall. Few beluga whales were detected during fall 2013 and spring 2014. Bearded seal (Erignathus barbatus) calls were detected mainly during spring (mating period). A small number of bowhead whale calls (Balaena mysticetus) were detected during fall 2013 and spring and summer 2014. For the first time at this latitude in Baffin Bay, long-finned pilot whales (Globicephala melas) and sperm whales (Physeter macrocephalus) were detected during summer and fall. Our results suggest that the presence of marine mammals in Baffin Bay and Melville Bay is governed mainly by the annual cycle of sea ice formation and decay.Le développement de l’exploration des hydrocarbures dans le nord-ouest du Groenland rend indispensable une meilleure compréhension de la présence des mammifères marins dans la région. La distribution saisonnière et spatiale des vocalisations de mammifères marins dans la baie de Baffin et la baie Melville sont décrites. Quatre AMAR (enregistreurs acoustiques autonomes multicanaux) ont été déployés durant l’été 2012 (de la fin de juillet au début d’octobre), cinq enregistreurs en septembre 2013 et deux enregistreurs de la fin de septembre 2013 au début de septembre 2014. La présence des vocalisations de plusieurs espèces animales a été déterminée au moyen de leur détection automatique et d’une vérification manuelle. Une approche novatrice pour distinguer les clics de narvals (Monodon monoceros) des clics de bélugas (Delphinapterus leucas) a été utilisée lors du processus de vérification. Les vocalisations de narvals ont été détectées au printemps et à l’automne, reflétant des directions de migration du sud au nord au printemps et du nord au sud à l’automne. Peu de bélugas ont été détectés à l’automne 2013 et au printemps 2014. Les vocalisations de phoques barbus (Erignathus barbatus) ont été principalement détectées durant le printemps (période de reproduction). Un petit nombre de vocalisations de baleines boréales (Balaena mysticetus) a été détecté à l’automne 2013 ainsi qu’au printemps et à l’été 2014. Pour la première fois à cette latitude dans la baie de Baffin, des globicéphales (Globicephala melas) et des cachalots (Physeter macrocephalus) ont été détectés en été et en automne. Nos résultats suggèrent que la présence des mammifères marins dans la baie de Baffin et la baie Melville peut être principalement expliquée par le cycle annuel de la formation et du retrait de la glace

Signals from the deep: spatial and temporal acoustic occurrence of beaked whales off western ireland

Little is known of the spatio-temporal occurrence of beaked whales off western Ireland, limiting the ability of Regulators to implement appropriate management and conservation measures. To address this knowledge gap, static acoustic monitoring was carried out using eight fixed bottom-mounted autonomous acoustic recorders: four from May to December 2015 on Ireland\u27s northern slope and four from March to November 2016 on the western and southern slopes. Recorders ran for 205 to 230 days, resulting in 4.09 TB of data sampled at 250 kHz which could capture beaked whale acoustic signals. Zero-crossing-based automated detectors identified beaked whale clicks. A sample of detections was manually validated to evaluate and optimize detector performance. Analysis confirmed the occurrence of Sowerby\u27s and Cuvier\u27s beaked whales and Northern bottlenose whales. Northern bottlenose whale clicks occurred in late summer and autumn, but were too few to allow further analysis. Cuvier\u27s and Sowerby\u27s clicks occurred at all stations throughout the monitoring period. There was a significant effect of month and station (latitude) on the mean daily number of click detections for both species. Cuvier\u27s clicks were more abundant at lower latitudes while Sowerby\u27s were greater at higher latitudes, particularly in the spring, suggesting a spatial segregation between species, possibly driven by prey preference. Cuvier\u27s occurrence increased in late autumn 2015 off northwest Porcupine Bank, a region of higher relative occurrence for each species. Seismic airgun shots, with daily sound exposure levels as high as 175 dB re 1 mu Pa-2.s, did not appear to impact the mean daily number of Cuvier\u27s or Sowerby\u27s beaked whale click detections. This work provides insight into the significance of Irish waters for beaked whales and highlights the importance of using acoustics for beaked whale monitoring

Signals from the deep: Spatial and temporal acoustic occurrence of beaked whales off western Ireland

<div><p>Little is known of the spatio-temporal occurrence of beaked whales off western Ireland, limiting the ability of Regulators to implement appropriate management and conservation measures. To address this knowledge gap, static acoustic monitoring was carried out using eight fixed bottom-mounted autonomous acoustic recorders: four from May to December 2015 on Ireland’s northern slope and four from March to November 2016 on the western and southern slopes. Recorders ran for 205 to 230 days, resulting in 4.09 TB of data sampled at 250 kHz which could capture beaked whale acoustic signals. Zero-crossing-based automated detectors identified beaked whale clicks. A sample of detections was manually validated to evaluate and optimize detector performance. Analysis confirmed the occurrence of Sowerby’s and Cuvier’s beaked whales and Northern bottlenose whales. Northern bottlenose whale clicks occurred in late summer and autumn, but were too few to allow further analysis. Cuvier’s and Sowerby’s clicks occurred at all stations throughout the monitoring period. There was a significant effect of month and station (latitude) on the mean daily number of click detections for both species. Cuvier’s clicks were more abundant at lower latitudes while Sowerby’s were greater at higher latitudes, particularly in the spring, suggesting a spatial segregation between species, possibly driven by prey preference. Cuvier’s occurrence increased in late autumn 2015 off northwest Porcupine Bank, a region of higher relative occurrence for each species. Seismic airgun shots, with daily sound exposure levels as high as 175 dB re 1 μPa²·s, did not appear to impact the mean daily number of Cuvier’s or Sowerby’s beaked whale click detections. This work provides insight into the significance of Irish waters for beaked whales and highlights the importance of using acoustics for beaked whale monitoring.</p></div

Signals from the deep: Spatial and temporal acoustic occurrence of beaked whales off western Ireland - Fig 2

<p><b>Waveform (top) and spectrogram (bottom) of beaked whale clicks.</b> A Sowerby’s beaked whale click recorded at station 1 on 5 Sept 2015 at 14:26, a Cuvier’s beaked whale click recorded at station 3 on 29 Nov 2015 at 17:56, and a northern bottlenose whale click recorded at station 1 on 12 Sept 2015 at 20:10 (right; 512 Hz frequency resolution, 2.6 ms time window, 0.2 ms time step, Hamming window).</p

Acoustic monitoring stations using AMARs in the Atlantic Margin study area off western Ireland during 2015 (stations 1–4) and 2016 (stations 3 and 5–8).

<p>Acoustic monitoring stations using AMARs in the Atlantic Margin study area off western Ireland during 2015 (stations 1–4) and 2016 (stations 3 and 5–8).</p

Signals from the deep: Spatial and temporal acoustic occurrence of beaked whales off western Ireland - Fig 6

<p>Mean adjusted hours with Cuvier’s (top) and Sowerby’s (bottom) beaked whale clicks with standard error bars in four light periods: dawn, light, dusk, and dark. Light period times were obtained from <i>Reda and Andreas (62)</i>. Results of Welch’s ANOVA are given for each species and results from Tukey-Kramer multiple comparisons tests are represented by coloured means with different colours denoting statistically significant differences. *The Sowerby’s light period does not differ significantly from any of the other light periods.</p

Signals from the deep: Spatial and temporal acoustic occurrence of beaked whales off western Ireland - Fig 8

<p><b>Mean Sowerby’s beaked whale detections per recording day bubble plot (right) and with standard error bars (left) for stations 1 (SE = ±1.28), 2 (SE = ±0.56), 3 (SE = ±0.70), 4 (SE = ±0.81), 5 (SE = ±0.51), 6 (SE = ±0.37), 7 (SE = ±0.23), and 8 (SE = ±0.15) off western Ireland from May to Dec 2015 (stations 1–4) and Mar to Nov 2016 (stations 3 and 5–8).</b> Results of Kruskall-Wallis tests are given and results from Tukey-Kramer multiple comparisons tests are represented by coloured means (left) with different colours denoting statistically significant differences. ^Station 4 does not differ from 3 or 5. *Station 7 does not differ from 8 or 6, but 8 differs from 6.</p